When an object is viewed with a monocular or a binocular telescope without a support or stand or the like, there is always the risk of shaking movements blurring the image. The cause for such shaking movements may be from the inability of the user to hold the device steady, or from external influences, such as the force of strong wind, or the movement of a boat or airplane on which the user is riding.
All this has the effect that in spite of highly developed optical imaging systems the theoretical resolution and discernability of details on the object under observation may in practice not be fully taken advantage of.
It has turned out that from the six possible movements of a telescope, namely the three linear movements along axes of a Cartesian coordinate system as well as the three rotational movements about these axes, essentially only the rotational movements about the two axes orthogonal to the optical axis (direction of vision), i.e. the rotational movements about the vertical axis and about the transverse axis are responsible.
In order to avoid the problems discussed above, various suggestions have become known. Some known suggestions are based on a concept according to which optical elements are movably supported within the ray path of the telescope, and are stabilized by means of inertial devices, for example by gyros.
These prior art suggestions have the disadvantage that relatively large masses must be provided and moved, respectively. Such telescopes, therefore, are relatively heavy and must be manufactured with high precision.
For binoculars one has the additional problem that the stabilizing measures in the two barrels must be coordinated.
More recent suggestions utilize an active stabilization instead of the above discussed purely mechanic and passive stabilization. When doing so, sensors measure the shaking movement of the barrel or barrels, respectively. An electronic position control compensates the barrel movement by means of actuators generating an oppositely directed movement of optical elements within the ray path of the telescope.
U.S. Pat. No. 4,235,506 discloses a binocular telescope. In this prior art telescope there is an inverting system, namely a prism, arranged within each of the barrels. The two prisms are gimballed.
This telescope has the disadvantage that a compensation of shaking movements is not always possible in an optimal way.
German disclosure document DE 15 47 129 A discloses a periscope in a vehicle having means for displacing a prism to compensate vehicle movements. The prism is a unit separate from the eyepiece.
U.S. Pat. No. 6,078,436 discloses a device for compensating jitter movements in a binocular telescope. The device comprises a movable plate having two lenses. In each of the barrels the inverting system and the eyepiece configure a common assembly, however, for adjusting the pupillary distance only.
A similar device is disclosed in U.S. Pat. No. 5,917,653.
U.S. Pat. No. 6,191,888 discloses a binocular telescope with a device for compensating shaking movements in which both the eyepiece and the inverting system are rigidly connected to the barrel, whereas the objective lens is displaceable for compensating such movements.
Another binocular with an image-vibration compensation system is disclosed in U.S. Pat. No. 6,226,123.